I noticed the skybox was "burning" into the screen, so I had to undo the recent changes. But, I added a nice fade effect at the base of the crystals and increased the refraction and color multiplier, so they now look more opaque and colorful.

I've also made numerous updates to other aspects of the project...

I updated the water, so the under-surface is more transparent. I updated the terrain generation and decreased some of the quality settings so it loads faster. I adjusted the colors and tint of the grass, in attempt to get it to blend better, which has been an on-going challenged for me in Unity.